Security element for data carrier

ABSTRACT

The invention relates to a security element for a data carrier, such as banknotes, securities, checks, credit cards, ID cards and similar documents. A substrate comprises a first layer of material and at least a first opaque layer ( 3 ) of material covering partially or totally the first layer of material. The first layer has at least two adjacent zones ( 1,2 ) of a different color. The element further comprises a pattern ( 4 ) formed by a partial engraving of said opaque layer ( 3 ). The pattern ( 4 ) extends at least partially on each of said zones ( 1,2 ) so that the pattern ( 4 ) comprises adjacent parts of different color in perfect register apparent through said opaque layer ( 3 ).

The present invention concerns a security element for a data carrier,such as banknotes, securities, checks, credit cards and ID cards andsimilar documents.

The present invention also concerns a data carrier comprising such asecurity element and a process for producing a data carrier comprising asecurity element according to the invention.

In the field of banknotes and securities, there has been increasingneeds for security features protecting against counterfeiting. Indeed,in the past years, computers, scanners and copy machines have beenextensively developed and today, it is possible to buy veryhigh-performance devices at a reasonable price. Since these devices aremore efficient, it has been at the same time necessary to develop newand improved security features for securities, such as banknotes,checks, cards (i.e. credit cards), ID cards, passports etc. which wouldnot allow them to be copied by standard computers or scanners, or evenmodern color copy machines.

Such security features include special inks, so called opticallyvariable inks (OVI) or other inks with iridescent properties, used toprint specific patterns on the substrate of the note, optically variabledevices (OVD) in the shape of metallized patches or holograms, or alsospecific patterns, such as moiré patterns and other similar patterns,all of which are very difficult if not impossible to copy with actualdevices, but, on the other hand, are easy to control visually.

Other security means include combinations of superimposed lines and/orpatterns with colors, which are only visible under specific conditions,for example UV light or by transparency. Again, the interest of suchsecurity features is that they may easily be printed or placed on thedocument to be protected and also be controlled by simple devices, evenvisually, but they are impossible to reproduce with actual printers,scanners or copy machines.

Another specific technique involves watermarks in which the papersubstrate is marked with lines or patterns only visible in transparency.A further development of this technique concerns pseudo-watermarksconsisting in the creation of a window in the substrate, especially inpaper-based substrates which are normally not transparent, said windowbeing transparent.

U.S. Pat. No. 6,082,778, the content of which is incorporated herein byreference, discloses an ID card protected from unauthorized reproductionwith a copying machine. In this patent, the basic idea of the inventionis to create a security element by combining the copy protection effectfrom a thin metal layer with the physical, in particular optical,properties of a further layer whose interplay prevents the identity cardfrom being reproduced. Under a transparent card cover layer, there is ametal layer over a layer having special optical properties. In a firstembodiment, the metal layer is locally demetalized thereby exposing thelayer with special optical properties, i.e. making it visible in thedemetalized area. The difference of contrast between the layers makesthe marks easy to recognize by the eye. In a particular favorableembodiment, the layer having special optical properties is dark-colored,in particular black. Indeed, the combination of the direct reflection ofthe metalized area and a strong absorbent layer (black layer forexample) prevents the detector of a copier from detecting a differencein contrast so that the marked information totally disappears.

In another embodiment disclosed in this patent, the layer having specialoptical properties contains fluorescent or phosphorescent substanceswhich, when irradiated by the light of the copier are not induced toemit light of a wavelength in the optically visible spectral range.Thus, the marked area is not reproduced by the copier.

Further, in the field of offset printing groups, several colors arecombined to produce printed color images. These colors usually are cyan,magenta, yellow and black and appropriate combination of these colorsallows any color to be printed. In standard offset printing groups, eachof said color is printed in an independent manner, i.e. differentsuccessive printing groups (one for each color), so that it is verydifficult to obtain a proper register between the colors, either on eachside of the printed matter, or even in a recto-verso register.

The aim of the invention is to create a new security element for datacarriers.

In particular, an aim of the invention is to provide a security element,which is very difficult to copy or counterfeit with standard modernscanners, copy machines and other equivalent devices and also to printwith current printing machines.

Another aim of the invention is to provide a security element, which iseasy to produce with the actual machines used for fabricating datacarriers comprising security elements.

Another aim of the invention is to provide data carriers, such asbanknotes, securities, checks, credit cards, ID cards and similardocuments with an improved security element, said data carrier beingvery difficult, if not impossible, to copy and to reproduce with moderncopying devices, for example scanners, copy machines and equivalentdevices and also with current printing machines.

A further aim of the invention is to provide a process for forming asecurity element according to the invention.

One aspect of security printing is the variability of the information onthe security document. Example: the serial number on the banknote.However, individual serial numbers do not offer an intrinsic securityagainst copy or reproduction. On the contrary, the process for forming asecurity element according to the present invention aims to offer bothaspects of security: the aspect of the variability and the aspect of theintrinsic impossibility to copy and reproduce.

These aims are fulfilled by the new and inventive features as defined inclaims 1 to 18.

A security element according to the invention has demonstrated to bevery efficient, impossible to copy and very difficult to counterfeitwith standard printing machines since a good register between the colorsis impossible to obtain. The effect is similar to the so-called orlofftechnique which is obtained with a machine as disclosed in U.S. Pat. No.5,036,763 (simultaneous multicolor recto-verso printing), the content ofwhich is incorporated by reference to the present application.

Further, the security element according to the invention uses aprinciple contrary to the one taught by U.S. Pat. No. 6,082,778 citedabove. In this patent, the idea is to take benefit of the high contrastbetween the non-removed layer (metalized layer) and the layerunderneath, made of a dark-colored surface, e.g. black, which is exposedby removal of the metalized layer.

In the present invention, in addition, it is important to see bothlayers, especially zones of different colors and thus be able to controldirectly the register of pattern. Since the shape of the pattern may bevery thin, it becomes impossible to preserve a perfect register ofcolors when copying the security element with a scanner, a copy machine,or when printing with standard printing machines, therefore a perfectregister is only possible with original security elements.

Additional security can be provided by correlating the variableinformation of the security element of the invention with anothervariable information on the carrier, for example, the serial number.This correlated information of the security element can be crypted andcoded by known techniques.

Further characterizing features and advantages of the present inventionwill become apparent from the following detailed description, given byway of non-limitative examples, and illustrated by the accompanyingdrawings, in which

FIGS. 1A to 1D show a first embodiment of the security element accordingto the invention.

FIG. 2 shows a second embodiment of the security element according tothe invention.

FIG. 3 shows a third embodiment of the security element according to theinvention.

FIG. 4 shows a first type of data carrier comprising a security elementaccording to the invention.

FIG. 5 shows another type of data carrier comprising a security elementaccording to the invention.

FIG. 6 shows a bloc diagram of a process according to the invention.

The first embodiment of the security element according to the presentinvention is described with reference to FIGS. 1A to 1C.

In FIG. 1A, two zones 1, 2 of a first layer are shown, both zones 1, 2having a different color, which is schematically represented by a brightzone 1 and a dark zone 2. Said zones are represented both with arectangular shape, however, other equivalent shapes are possible, suchas circular shapes, or combination of any kind of shapes (rectangularand circular, for example). This layer forms a background that may beprinted on a substrate, for example by offset printing, a knowntechnical printing process. Other printing techniques are of coursepossible.

In FIG. 1B, both zones 1 and 2 forming the first layer are representedwith broken lines, and said first layer is covered by an opaque layer 3.For the sake of clarity, opaque layer 3 is shown transparent, however isit clear that this layer 3 is in fact opaque. This opaque layer 3 ismade of an ink comprising metallic particles, for example an opticallyvariable ink (so-called “OVI”) known in the art or by an opticallyvariable device (so-called “OVD”). Preferably, but not limited thereto,the ink is deposited by using a silk screen printing technique. Similariridescent type of inks may also be deposited with flexographic orgravure printing processes.

In FIG. 1C, a pattern 4 has been formed in the security element of FIG.1B, by engraving the opaque layer 3 along a given path to make the firstlayer (Zones 1 and 2) visible. The pattern is the number “1” but thisrepresentation is not limiting and any pattern is possible, i.e.alphanumeric characters and/or geometric shapes. For the sake ofclarity, both zones 1 and 2 are still represented as if the layer 3 wastransparent, but the effective result is represented in FIG. 1D, inwhich the second layer 3 is represented as being opaque. Thus, thepattern 4 comprises two parts 5 and 6 of different color, that is thecolor of the respective zone 1 or 2 forming the background.

Since both parts 5 and 6 are not printed separately but are the resultof the engraving of a part of an opaque layer, the register is perfectand could never be obtained if both parts 5, 6 were printed separately.

In order to engrave the opaque layer 3, one uses a laser apparatus, forexample a yag (yttrium-aluminum-garnet) laser as known in the art. Thislaser engraves the layer 3 containing material reacting with the laserdepending upon the absorption coefficient of said material, and the beamdoes not react with the zones 1, 2 of the first layer that form thebackground. The laser beam must be monitored, either directly by movingthe laser, along a preset path, or indirectly through mirrors to followa predetermined path in order to form the requested pattern. Suchpattern may form invariable information, identical for each securityelement, or variable information (for example a sequence of numbersand/or letters), which changes for each security element created. Theengraving is made by burning or sublimation or other similar processinduced by the laser radiation. The engraving can be variable from onedata carrier to another. The engraving can be correlated to anothervariable information on the carrier, and also crypted and coded by knownmeans.

In a second embodiment, represented in FIG. 2, the pattern 8 (number“1”) may be formed by engraving the opaque layer 3 along a thin linethat follows the periphery of the desired pattern. In this case, thepattern 8 is formed of several segments, segments 9, 10 11 having zone 2(see FIG. 1B) as background, hence the color of zone 2, and segments 13to 18 having zone 1 as background, hence the color of said zone 1. Thisembodiment is particularly advantageous in that the thin lines aredifficult to copy as such, and it becomes even more difficult to obtaina perfect register between the segments and the colors, because of theirsmall size.

A third embodiment, as represented in FIG. 3, comprises a first layerwith twenty one zones (Z1 to Z21) of at least two different colors, thefirst opaque layer 3 similar to the layer described in the otherembodiments, and a second opaque layer 19, covering at least partiallythe first opaque layer 3 and the zones of the first layer. For example,said second opaque layer 19 may be made of a further security element,such as an optically variable device made of any material reacting withthe laser beam as mentioned previously (so called OVD), which is commonin the art, in the form of a patch. This patch comprises a metalizedsurface that reflects light and is nearly impossible to copy with copymachines, or to reproduce with scanners. Since this second opaque layer19 is made of a different material than the first opaque layer 3, it mayreacts in a different manner when exposed to the laser beam. Forexample, the same laser beam may produce pattern of different width inthe first opaque layer 3 and in the second opaque layer 19. It is thuspossible to vary the width of parts of the pattern with the same laserbeam, which makes the security element even more difficult to copy. Ithas not only different colors in perfect register, but at the same timeportions of different widths also in perfect register. However, bothopaque layers may also be of the same material but in different colors.In the embodiment of FIG. 3, a first pattern 20 (number “1”) is engravedin the first opaque layer 3 and extends over the zones Z4, Z5, Z6, Z7and Z8. A second pattern 21 formed of three parallel and horizontallines is engraved both on layer 3 and layer 19 extending, respectively,over zones Z7, Z10 and Z13; Z8, Z11 and Z14; Z9, Z12 and Z15. A thirdpattern 22 (letter “A”) is also engraved in layer 19 over zones Z16,Z17, Z18, Z19, Z20 and Z21.

This embodiment is particularly advantageous in that it combines severalzones of different colors, two opaque layers that may be of twodifferent materials and patterns engraved in each opaque layer and in apart in which the opaque layers overlap each other.

Of course, depending on the material chosen to form the layers the widthof the pattern may increase or decrease, FIG. 3 being only given as anon-limiting example.

In FIG. 4, the data carrier is represented as a note 23, such as abanknote or a check. The note 23 is made, as known in the art, of asubstrate, such as a paper substrate or a polymer substrate, or aplastic substrate on which a security element 24 according to theinvention is printed. This note 23 comprises a security element asdisclosed in one of the embodiment of FIGS. 1D, 2, or 3. The securityelement 24 comprises a number “1” and a letter “X”. Therefore, thesecurity element according to the invention could be used for numberingsuccessive notes, when each note receives a different number. This isparticularly useful for printing variable information, such as serialnumbers: since the device used to engrave the second layer 3, forexample a laser beam, may be guided to form any pattern, it is very easyto use it for numbering successive notes in addition of classicaldevices that print numbers. The laser beam can engrave correlatedinformation to another variable information such as the serial number,and this engraved information can be crypted and coded by known means

For the sake of representation, the security element 24 corresponds tothe embodiment of FIG. 1D; however, the other embodiments of FIGS. 2 and3 are possible, either alone, or in any combination on the same note.This combination is shown schematically in FIG. 4, in which, as said,element 24 could correspond to the embodiment of FIG. 1D, elements 25and 26 could correspond to the embodiment of FIG. 2, and element 27could correspond to the embodiment of FIG. 3, for example. Anycombination would further improve the features of the note in that itwould be even more difficult to copy of counterfeit since it carriesdifferent embodiments of a security element. It is also possible tocombine the security elements on both sides of the substrate, using oneelement on one side and another (identical or different) on the otherside.

In a further embodiment, disclosed in FIG. 5, the background with atleast two zones of a different color may not be printed on the substratebut could be formed by the substrate itself. This is particularly usefulfor substrate made of plastic or similar products (as used for examplefor ID cards, credit cards and EC cards), which may easily be producedwith a multicolored substrate. Of course, this principle may be appliedto all substrate.

In the example shown in FIG. 5, a substrate 28 comprises two parts 29and 30 of a different color, as schematically represented by a brightpart 29 and a dark part 30. The parts 29, 30 are equivalent to the zones1 and 2 of FIG. 1.

A security element 31 is present on the substrate 28, said element 31comprising, as described here above, an opaque layer 32, for example alayer of optically variable ink, in which a pattern has been created byremoving the layer 32 along a given path. As an example, the pattern hasthe shape of the number “1” with two colors, the upper part 33 of thecolor of part 30 and the lower part 34 of the color of part 29.

The principles described above for the embodiments of FIG. 2 or 3 on thesubstrate of FIG. 4 may be used for this substrate. It is also possibleto further combine in this embodiment the security element 31 using thedifferent colors of the substrate itself as background with anothersecurity element in which the background of two or more colors isprinted on the substrate, i.e. to apply a security element similar tothe elements 24, or 25, or 26 or 27 shown in FIG. 4 on the substrate 28of the embodiment of FIG. 5. This variant is schematized by the element35 in FIG. 5 corresponding schematically to the element of FIG. 1B, inwhich no specific pattern has been marked yet. Of course, anycombination is possible, not only on the same side of the substrate, butalso on both sides of the substrate.

A process suitable for producing a security element according to theinvention is shown schematically in the block diagram of FIG. 6.

The first step comprises the provision of a substrate with a first layerhaving at least two adjacent zones of different color. As disclosedabove, said two zones may be printed on the substrate or they may beformed by the substrate itself, or they may be partially printed on thesubstrate and partially formed by the substrate.

The second step comprises covering at least partially said adjacentzones with a first layer that is opaque.

In the third step, said opaque layer is engraved, preferably via ayag-laser beam, to form a pattern, for example a number, a sequence ofnumbers, a letter, a sequence of letters or a combination of both tomake the first layer apparent. As described above, it is possible toengrave the opaque layer corresponding to the exact pattern to be formed(see FIG. 1D), or, in another variant, to draw the pattern by engravingthin lines corresponding to the periphery of the pattern to be formed(see FIG. 2).

The embodiments described above are given by way of examples and are notlimiting.

As a further development of the invention, it is possible to use threeor more colors for the background, resulting in patterns having parts ofthree different colors or more, according to the principle of theinvention.

1. Security element for a data carrier, such as banknotes, securities,checks, credit cards, id cards and similar documents, with a substratecomprising a first layer of material and at least a first opaque layerof material covering partially or totally said first layer of materialwherein said first layer has at least two adjacent zones of a differentcolor, in that the element further comprises a pattern formed by apartial engraving of said opaque layer, wherein said pattern extends atleast partially on each of said zones so that said pattern comprisesadjacent parts of different color in register apparent through saidopaque layer.
 2. Security element as claimed in claim 1, wherein saidfirst layer is printed on said substrate.
 3. Security element as claimedin claim 1, wherein said first layer is formed by said substrate. 4.Security element as claimed in claim 1, wherein first layer is partiallyformed by said substrate and partially printed on said substrate. 5.Security element as claimed in claim 1, wherein it comprises a secondopaque layer covering at least partially said first layer and said firstopaque layer, said pattern being formed by a partial engraving of saidfirst and second opaque layers.
 6. Security element as claimed in claim1, wherein said opaque layer is made of an optically variable ink, or ofan optically variable device or of a combination of both.
 7. Securityelement as claimed in claim 1, wherein said pattern is formed byengraving said opaque layer or layers along a shape corresponding tosaid pattern.
 8. Security element as claimed in claim 1, wherein saidpredetermined pattern forms variable information which varies from onedata carrier to another.
 9. Security element as claimed in claim 8,wherein said pattern is correlated with another variable information onthe data carrier.
 10. Security element as claimed in claim 9, whereinsaid correlated pattern is crypted and coded.
 11. Security element asclaimed in claim 1, wherein said pattern is formed of alphanumericcharacters and/or geometric forms.
 12. A data carrier, such asbanknotes, securities, checks, credit cards or ID cards comprising asecurity element as claimed in claim
 1. 13. A process for forming a datacarrier as claimed in claim 11 with a security element, said processcomprising the following steps: providing a substrate with a first layerof material having at least two adjacent zones of a different color anda first opaque layer of material covering at least partially said firstlayer of material engraving said first opaque layer to form a pattern,whereby said pattern extends at least partially on each of said zones sothat said pattern comprises adjacent parts of different color inregister apparent through said opaque layer.
 14. A process as claimed inclaim 13, wherein said first layer is printed on said substrate.
 15. Aprocess as claimed in claim 13, wherein said first layer is formed bysaid substrate.
 16. A process as claimed in claim 13, wherein saidsubstrate is provided with a second opaque layer covering at leastpartially said first layer and said first opaque layer, said patternbeing formed by engraving said first and second opaque layers
 17. Aprocess as claimed in claim 13, wherein said opaque layer is made of anoptically variable ink, or of an optically variable device, or acombination of both.
 18. A process as claimed in claim 13, wherein saidpattern is formed by engraving said opaque layer or layers along a shapecorresponding to said pattern.
 19. A process as claimed in claim 18,wherein said engraving of said opaque layers is made by a laser. 20.Security element as claimed in claim 5, wherein said opaque layer ismade of an optically variable ink, or of an optically variable device orof a combination of both.
 21. A process as claimed in claim 16, whereinsaid opaque layer is made of an optically variable ink, or of anoptically variable device, or a combination of both.
 22. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 2. 23. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 3. 24. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 4. 25. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 5. 26. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 6. 27. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 7. 28. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 8. 29. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 9. 30. A data carrier,such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim
 10. 31. A datacarrier, such as banknotes, securities, checks, credit cards or ID cardscomprising a security element as claimed in claim 11.